diff --git a/AST.cpp b/AST.cpp
index 3ecf79eb6..0827f7941 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -308,8 +308,8 @@ void FunctionDefinition::checkTypeRequirements()
 	{
 		if (!var->getType()->canLiveOutsideStorage())
 			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to live outside storage."));
-		if (!var->getType()->externalType() && getVisibility() >= Visibility::Internal)
-			BOOST_THROW_EXCEPTION(var->createTypeError("Type is required to have an external address."));
+		if (!var->getType()->externalType() && getVisibility() >= Visibility::Public)
+			BOOST_THROW_EXCEPTION(var->createTypeError("Internal type is not allowed for function with external visibility"));
 	}
 	for (ASTPointer<ModifierInvocation> const& modifier: m_functionModifiers)
 		modifier->checkTypeRequirements(isConstructor() ?
@@ -659,7 +659,7 @@ void MemberAccess::checkTypeRequirements()
 											  "visible in " + type.toString()));
 	//todo check for visibility
 //	else if (!m_type->externalType())
-//		BOOST_THROW_EXCEPTION(createTypeError("Type is required to have an external address."));
+//		BOOST_THROW_EXCEPTION(createTypeError("Internal type not allowed for function with external visibility"));
 
 	// This should probably move somewhere else.
 	if (type.getCategory() == Type::Category::Struct)
diff --git a/Types.cpp b/Types.cpp
index 6fe8a6410..82c28a394 100644
--- a/Types.cpp
+++ b/Types.cpp
@@ -749,7 +749,9 @@ TypePointer ArrayType::externalType() const
 	if (m_isByteArray)
 		return shared_from_this();
 	if (!(m_baseType->externalType()))
+	{
 		return TypePointer();
+	}
 	if (dynamic_cast<ArrayType const*>(m_baseType.get()) && m_baseType->isDynamicallySized())
 		return TypePointer();
 
diff --git a/Types.h b/Types.h
index 013c65893..5941646aa 100644
--- a/Types.h
+++ b/Types.h
@@ -263,7 +263,6 @@ public:
 	virtual std::string toString() const override;
 	virtual u256 literalValue(Literal const* _literal) const override;
 	virtual TypePointer getRealType() const override;
-	virtual TypePointer externalType() const override { return shared_from_this(); }
 
 	/// @returns the smallest integer type that can hold the value or an empty pointer if not possible.
 	std::shared_ptr<IntegerType const> getIntegerType() const;
@@ -298,6 +297,7 @@ public:
 
 	virtual std::string toString() const override { return "bytes" + dev::toString(m_bytes); }
 	virtual u256 literalValue(Literal const* _literal) const override;
+	virtual TypePointer externalType() const override { return shared_from_this(); }
 
 	int getNumBytes() const { return m_bytes; }
 
@@ -323,6 +323,7 @@ public:
 
 	virtual std::string toString() const override { return "bool"; }
 	virtual u256 literalValue(Literal const* _literal) const override;
+	virtual TypePointer externalType() const override { return shared_from_this(); }
 };
 
 /**